Resinous compositions of starch ethers with other resins



Patented Jan. 4, 1949 RESINOUS COMPOSITIONS F STARCH ETHERS WITH OTHERRESINS Peter L. Nichols, Jr., and Lee T. Smith, Philadelphia, Paauignors to the United States of America as represented by the Secretaryof No Drawing. Application January 26, 1945, Serial No. 574,668

4 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) This application is made under the act of March 3, 1883, asamended by the act of April 30, 1928, and the invention hereindescribed, if patented, may be manufactured and used by or for theGovernment of the United States of America for governmental purposeswithout the payment to us of any royalty thereon.

This application is a continuation in part of our copending applicationfor patent. Serial No. 518,979, filed January 20, .1944, and nowabandoned.

This invention relates to the preparation of improved resinouscompositions. and moreparticularly to compositions of various resins,such as the acrylate and vinyl resins having improved properties.

We have found that by adding starch ethers, such as the unmixed starchethers benzyl starch and allyl starch, to resins, resinous compositionshaving substantially improved properties can be obtained. We have alsofound that mixed ethers or ether-esters of starch such as methyl benzylstarch, ethyl benzyl starch, ethyl ally starch,

benzyl starch acetate, allyl starch acetate, can be added to resins toproduce similar improvements. The expression starch ethers" is employedin the generic sense, being inclusive of, for example, mixed starchethers, unmixed starch ethers and starch ether-esters. The mixed resinsthus obtained can be used in preparing lacquers, impregnating fibrousand porous materials, coating paper, and in preparing molded objects orrigid plastics.

The mixing of starch ethers with the resins can be eflected either bydissolving them in a common solvent or by mixing them on a roller millor other suitable mixer. The amount of ethers or ether-esters added willdepend upon the use intended for the mixed resin, but in general notmore than one part of ether or ether-ester should be added to one partof resin. Higher proportions of ether will often produce brittlecompositions, although the addition of a plasticizer will A overcomethis effect to some extent. Ordinary plasticizers such as tri-o-cresylphosphate or butyl phthalate are satisfactory.

Our invention is illustrated by the influence of starch ethers onacrylic ester polymers. The polymers of methyl and ethyl acrylate, forinstance, are comparatively soft and tacky; their tensile strength islow; their softening temperature is low; their point of brittleness ishigh; and they are compatible with only a few other resins. All of theseproperties limit their use.

We have found, on the other hand, that the ad- 2 dition of benzyl orallyl starch (1.4 to 214 allyl groups per glucwe unit) to methyl andethyl acrylate polymers 1) strength; (2) raises the temperature ofsoftening; (3) lowers the temperature of brittleness; (4) reduces thetackiness; and (5) increases the hardness but retains flexibility. Theresulting compositions have, accordingly, a substantially greaterutility than the acrylate polymers used alone.

. The following examples are representative of our invention:

Example I Ninety parts of methyl acrylate (medium viscoslty) dissolvedin ethylene chloride was shaken with a solution of 10 parts of benzylstarch (2.2 benzyl groups per glucose unit) in ethylene chloride. Thesolvent was allowed to evaporate and the resultant film was baked 24hours at C. The resulting composition was opaque but appeared to bequite homogeneous in structure. It was tough and moderately flexible.The tensile strength of the original methyl acrylate was 700 p. s. i.The tensile strength of the methyl acrylate modified with benzyl starchwas 3000 p., s. i. The brittle point determined by a. stand ard test ofthe original methyl acrylate was approximately 5 C. The modified methylacrylate had a brittle point near 40 C. The modified product softened 20to 30 C. higher than the original methyl acrylate. In anotherexperiment, a methyl acrylate polymer possessing considerable tack wasmixed with benzyl starch. The resulting film was tack-free. Films ofmethyl acrylate and allyl starch were trans-.

parent and had essentially the same properties as those described forthe methyl-acrylatebenzyl starch compositions.

Example II Example 111 One hundred parts of methyl methacrylate polymerand 5 parts of gummy allyl starch (approximately 2 allyl groups perglucose unit) were mixed on regular compounding rolls for atwelveincreases the tensile minute period. The resulting product wasmolded in a press for ten minutes under the conditions described inExample II. The molded product had a slight haze.

Example IV One hundred parts of polystyrene and 25 parts of gummy allylstarch (approximately 2 allyl groups per glucose unit) were mixed onregular rubber compounding rolls for a period of seventeen minutes. Theresulting product was molded in a press under the conditions describedin Example II. The molded product was opaque and hard.

, Example V One hundred parts of polyvinyl acetate (medium viscosity)and 25 gms. o1 gummy allyl starch (approximately 2 allyl groups perglucose unit) were mixed on regular compounding rolls im afifteen-minute period. The resulting mate- 4 having about 1.4 to 2.4ether groups per glucose unit.-

2. A resinous product prepared by the process defined in claim 1. 1

3. A process oi! improving the physical properties of methyl acrylatepolymer comprising incorporating therewith an ally] starch ether havingabout 1.4 to 2.4 ether groups per glucose unit.

4. A process of improving the physical properties of a lower alkylacrylate polymer comprising incorporating therewith an allyl starchether having about 1.4 to 2.4 ether groups per glucose unit.

PETER L. NICHOLS. Ja. LEE T. SMITH.

REFERENCES CITED The following references are ot-record in the file ofthis patent:

v UNITED STATES PATENTS Number Germany June 22, 1933

